Why was the Athanasian Creed unknown in the Eastern Church until the 12th century?

The Athanasian Creed was unknown in the Eastern Church until the 12th century because it was a Latin document composed in the Western Church. While its exact origins are debated, scholars generally agree it was likely composed in southern France during the 5th century, not by Athanasius himself.1

The Eastern and Western churches had developed separately due to differences in language, culture, politics, and religion. The Eastern churches, centered in Constantinople, followed their own course, emphasizing the administrative independence of national churches rather than the centralized authority seen in the West with the bishop of Rome. These divergences contributed to the eventual schism between the two branches of Christianity.2